(1) Field of the Invention
The present invention relates to a device for measuring a mass flow with a guide means having a surface shaped as a circular arc, over which the mass flow can flow during the measurement, and a force sensor.
(2) Description of Related Art
The German published application DE 18 02 213 discloses a device of this type. The guide means of the device is pivotally supported and has an extension arm which operates on the force sensor when the guide means performs a pivoting motion. During the flow across the guide means, a mass flow flowing across the guide means experiences a centripetal force that is proportional to the moving mass. A force in the opposite direction counteracts the centripetal force applied by the guide means on the moving mass, which in conjunction with the friction forces generated by the mass particles produces a pivoting motion of the guide means about its pivot point. The torque of this pivoting motion is transferred to the force sensor by the extension arm of the guide means. The force sensor generates from the torque a sensor signal which corresponds to the force exerted by the force transfer point on the extension arm on the pivot point where the force sensor is located.
The location of the pivot point of the guide means can be defined in a manner described in the published application, which discloses that effects, which are produced by the friction of the mass particles during their flow along the guide means, are substantially compensated with the predefined location of the pivot point of the guide means. However, the method disclosed in the printed application for determining the pivot point is only qualitative. A quantitative method for determining the pivot point that is mathematically or mechanically founded is not disclosed. Compared to the conventional methods for determining mass flow, the device disclosed in the published application is superior, but does not satisfy the requirements for an exact measurement of the mass flow, where all effects caused by friction need to be compensated.
It is therefore an object of the invention to design a device of the aforedescribed type so that the mass flow can be measured with greater accuracy than before. In particular, effects caused by friction between the mass particles and the guide plate are compensated.